CoupledSDEs documentation

[JonasKoziorek]

Describe the bug
I think that the CoupledSDEs part of the documentation should be better incorporated into the rest of the docs. Other types of dynamical systems such as CoupledODEs or PoincareMap have their documentation under DynamicalSystemsBase.jl section but CoupledSDEs have their own section which break this pattern.

Example

[Datseris]

Yeah, probably we need to rethink this a bit. At the moment the standard tutorial/documentation for how to make a typical system CoupledODEs/Map is in the main DynamicalSYstems.jl tutorial. Here only the docstrings are expanded. Because the SDE version is significantly more complex, we felt it needed a dedicated doc page. And it does.

So, ideally, one would have full proper documentation for all types of dynamical systems here. But I simply haven't had the time to contribute it (and honestly it is probably low priority; the docstrings are very good).